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Energy
The capacity to supply heat or do work.
Law of conservation of energy(1st Law of thermodynamics):
during a chemical or physical change, energy can be neither created nor destroyed, although it can be changed in form (ΔU= q+w)
What are the 2 main types of energy?
Potential Energy & Kinetic Energy
Potential energy (PE)
the energy an object has because of its relative position, composition, or condition.
Kinetic energy (KE)
the energy that an object possesses because of its motion.
Thermal energy
kinetic energy associated with the random motion of atoms and molecules ( Thermometers are speedometers for atoms)
How does Thermal Energy Flow
Thermal energy always flows from the high T substance to the low T substance
Temperature
= average kinetic energy
Fast moving molecules ➔ “Hot”
Slow moving molecules ➔ “Cold”
calorie (cal)
amount of energy required to raise one gram of water by 1 °C (or 1 kelvin).
Calorie (with a capital C),
large calorie, commonly used in quantifying food energy content, is a kilocalorie.
joule (J)
amount of energy used when a force of 1 newton moves an object 1 meter.
What is the ratio of Joules to calories
1cal=4.184J
Enthalpy (ΔH)
total heat content of the system
Heat (q)
transfer of thermal energy between two bodies at different temperatures.
The system
In chemistry, the system is usually defined as the substances involved in chemical and physical changes.
The surroundings
In chemistry, the surroundings generally include the solvent and container.
exothermic process
A change that releases heat into the surroundings (-q)
endothermic process
A change that absorbs heat from the surroundings (+q)
Closed System
Only Energy can go into and out of a closed system, but matter cannot
Open System
Matter and Energy can Be transferred into and out of the system
Isolated System
neither energy nor matter can enter or leave
Insulated System
Minimized heat transfer, but possible transfer of work and matter.
heat capacity (C)
quantity of heat (q) absorbed or released when a body of matter experiences a temperature change (ΔT) of 1 °C (or 1 kelvin):
specific heat capacity (c)
quantity of heat required to raise the temperature of 1 gram of a substance by 1 °C (or 1 kelvin)
molar heat capacity (cm)
quantity of heat required to raise the temperature of 1 mole of a substance by 1 °C (or 1 kelvin)
If a substance gains thermal energy,
the final temperature is larger than the initial temperature (Tfinal > Tinitial), then the value of q is positive (q>0).
If a substance loses thermal energy,
the final temperature is smaller than the initial temperature (Tf< Ti), then the value of q is negative (q<0).
calorimeter
a device used to measure the amount of heat involved in a chemical or physical process.
What type of system does a calorimeter form
The inside of a calorimeter forms a closed and insulated system (qtot = 0).
If the reaction is exothermic,
he heat produced by the reaction is absorbed by the solution.
If the reaction is endothermic
the heat required for the reaction to occur is provided by the solution,
Note 
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